Atsushi Nemoto wrote:
> On Mon, 17 Apr 2006 15:07:35 +0100, Thiemo Seufer <ths@networkno.de> wrote:
> > I should have read more carefully. The ELF_R_SYM seems to be correct, if
> > this patch makes it work fo you then the toolchain you use creates broken
> > (word-swapped ?) relocation entries for mips64el.
>
> Looking at following codes in glibc source
> (sysdeps/mips/elf/ldsodefs.h), I thought r_info on 64bit mips needs
> special handling. Is not this structure used for 64bit kernel
> modules?
>
> typedef struct
> {
> Elf32_Word r_sym; /* Symbol index */
> unsigned char r_ssym; /* Special symbol for 2nd relocation */
> unsigned char r_type3; /* 3rd relocation type */
> unsigned char r_type2; /* 2nd relocation type */
> unsigned char r_type1; /* 1st relocation type */
> } _Elf64_Mips_R_Info;
Hm, binutils uses generically 64bit quantities:
#define ELF32_R_SYM(i) ((i) >> 8)
#define ELF32_R_TYPE(i) ((i) & 0xff)
#define ELF32_R_INFO(s,t) (((s) << 8) + ((t) & 0xff))
#define ELF64_R_SYM(i) ((i) >> 32)
#define ELF64_R_TYPE(i) ((i) & 0xffffffff)
#define ELF64_R_INFO(s,t) (((bfd_vma) (s) << 31 << 1) + (bfd_vma) (t))
But for MIPS64 the same as glibc:
typedef struct
{
/* Address of relocation. */
unsigned char r_offset[8];
/* Symbol index. */
unsigned char r_sym[4];
/* Special symbol. */
unsigned char r_ssym[1];
/* Third relocation. */
unsigned char r_type3[1];
/* Second relocation. */
unsigned char r_type2[1];
/* First relocation. */
unsigned char r_type[1];
/* Addend. */
unsigned char r_addend[8];
} Elf64_Mips_External_Rela;
/* MIPS ELF 64 relocation info access macros. */
#define ELF64_MIPS_R_SSYM(i) (((i) >> 24) & 0xff)
#define ELF64_MIPS_R_TYPE3(i) (((i) >> 16) & 0xff)
#define ELF64_MIPS_R_TYPE2(i) (((i) >> 8) & 0xff)
#define ELF64_MIPS_R_TYPE(i) ((i) & 0xff)
So it is the
r.r_info = TO_NATIVE(rela->r_info);
in modpost.c which breaks both SYM and TYPE because it assumes a
64bit integer. The proper solution would be to add a Elf64_Mips_Rela
structure (with lots of nearly identical duplicated code), the hack
would be to cast r_info to a 32bit integer for mips, before feeding
it to TO_NATIVE (which works until somebody asks for the TYPE, then
a separate mips64 version becomes inevitable.)
Thiemo
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